Frank
Wookie
Most dif services are done with a suction gun now-a-days, drain and fill. Xfer cases are mostly drain and fills as well. Trans and cooling systems are flushes now and that is the way to go especially the trans (auto). A typical auto trans hold 12-15 qts of fluid in the system and dropping the pan only changes a small fraction of the fluid usually about 4-5 qts. So a flush is way better because they open the cooler lines and totally flush the trans, torque converter, and the cooler.





